HS2: Heidi Alexander to set out true cost of rail project – and when trains will begin to run

Transport secretary to give budget details of troubled high-speed line, which backers hope will stay well below 100bn

The latest estimate of the cost of HS2 and a timetable to complete construction of the high-speed railway will be set out by the government on Tuesday, including plans to run trains slower to trim costs.

The transport secretary, Heidi Alexander, is expected to give the first official reckoning of the troubled project's budget in 2026 prices, which HS2's backers hope will remain substantially below 100bn.